Brush construction



Feb. 11, 1964 R E L L M F m L (lberli mak umu ATTORNEYS United States Patent 3,120,671 BRUSH CONSTRUCTIGN Leon F. Miiler, Rocky River, Ohio, assignor to The Osborn Manufacturing Company, Cleveland, Ohio, a corporation of Ghio Filed Oct. 2, 1961, Ser. No. 142,204 5 Claims. (Cl. 15179) This invention relates as indicated to a novel brush construction, and more particularly to power driven rotary brushes having improved brushing efficiency and increased life.

Power driven rotary brushes are known in the art utilizing wire bristle material which may be provided with a vibration damping coating as taught in Peterson Patent 2,682,734 or embedded in a matrix of vibration damping elastomeric material as taught in Peterson Patent 2,826.- 776 and Stingley Patent 2,950,495, for example. It is also known to crimp such bristles to cause the latter mutually to support one another at points along their length and to twist such bristles together to form twisted tufts as shown in Peterson Patent 2,744,277 and Benyak Patent 2,755,- 496. It has become evident, however, that certain important advantages accrue from the employment of straight brush filaments which are not thus crimped or twisted, although a problem then arises of adequately supporting the same to avoid localized concentrations of stress in use which lead to early fatigue and long fracture of the bristle.

Twisted tuft rotary brushes which may be either wheel brushes, cup brushes or end brushes, for example, are extensively used in the art for a wide variety of brushing operations, including such operations as the cleaning of are welded joints, removal of mill scale and the like, the twisted bristles mutually supporting one another to a certain extent, but certain relatively hard filamentous material capable of especially good cutting action has not been suitable for employment in this manner since such materials cannot be successfully twisted due to their relatively brittle nature and tufts or bundles of such hard filaments extending directly parallel to one another do not adequately mutually support one another to prevent con centrations of stress and consequent long fracture especially in the region where the bristles emerge from the supporting base or hub. It is accordingly an important object of this invention to provide brushes and especially power driven rotary brushes utilizing tufts of hard straight bristle material in which the individual bristles are not deformed as by crimping or twisting, but the tufts themselves nevertheless are formed in a manner to obtain certain of the benefits previously obtained by such twisting.

Another object is to provide tufts of bristle material, and especially straight bristle material, shaped in a manner to facilitate securing such tufts in appropriate sockets or holders.

Still another object is to provide a brush bristle tuft in which the working ends of such bristles are uniformly spaced from one another.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a side view of a bundle of straight parallel bristles or filaments adapted to be modified in accordance with the invention to provide an improved form of brush tuft;

FIG. 2 is a side view of such bundle which has been twisted as a whole (without twisting or deforming the individual straight bristles) to skew such bristles relative to one another in a uniform manner;

FIG. 3 shows the tuft of FIG. 2 with the base end portion thereof treated with a bonding agent to secure such tuft with the bristles in such relatively skewed relationship;

FIG. 4 shows the tuft of FIG. 3 mounted within a cup shaped holder to provide a finished end brush;

FIG. 5 is a longitudinal section through the end brush of FIG. 4;

FIG. 5A is an end view of the tuft of FIG. 5 showing the uniform spacing and distribution of the bristle ends obtained by the tuft formation of this invention; and

FIG. 6 shows a wheel brush in which a plurality of such tufts are secured in a central annular hub with the tufts extending generally radially outwardly therefrom.

Referring now more particularly to said drawing, a bundle of straight parallel bristles l which may, for example, be formed of wires having a Knoop hardness of at least 600 may be gripped adjacent one end which is to constitute the inner or base end of the tuft and the tuft then subjected to a twisting action effective to skew the bristles relative to one another so that at least the outer bristles of the bundle are slightly inclined relative to the longitudinal axis of the bundle as shown in FIG. 2, the bundle thereby assuming a volumetric form generally of two frusto-conical portions having their narrower end faces opposed in the plane indicated by the line AA on FIG. 2. By this skewing action, the working end face 2 of the tuft is somewhat expanded and opened out and the base end portion 3 is similarly expanded although to a lesser extent, the tuft or bundle having a relatively constricted neck portion in the region of such line A-A. Accordingly, the bristles are constantly diverging from the parallel, although at a very slight angle.

The base portion of the skewed tuft thus formed may then be dipped or otherwise treated with an appropriate bonding agent 4 such as an epoxy resin or preferably an elastomeric material such as neoprene (polychloroprene) or polyurethane to secure the bristles together as a unit with their base end portions embedded in such elastomeric material. The brush elements thus produced are then ready to be seated and secured in appropriate sockets or other holders to form the finished brush. Thus, as shown in FIGS. 4 and 5, the treated bonded base portion 4 may be seated within a metal cup shaped holder 5 having an axially extending stem 6 with the lip 7 of the cup then being deformed inwardly in the region of the necked portion of the tuft to secure the latter against axial withdrawal. The tuft may be additionally secured in the holder by other known means such as an appropriate bonding agent, e.g. epoxy resin, provision of a key, or the like. The end brush thus produced will ordinarily preferably be rotated in use in a direction against the lay of the bristles to achieve a relatively strong efiective cutting action on the work, although the brush may alternatively be rotated in the other direction when a relatively soft finishing action is desired.

The novel tufts of this invention may also be mounted in a variety of other supports or holders to form tufted brushes of types generally well known in the art, As shown in 'FIG. 6, such tufts may be secured in an annular hub '8, as by clamping between a pair of deformed annular plate members to produce a wheel brush in which the tufts extend generally radially outwardly, and it will be readily apparent that the tufts may likewise be secured in appropriate holders to produce cup brushes, roller brushes and the like.

While many different types of brush bristles may be utilized in accordance with this invention, the invention is, as indicated, of particular advantage when utilizing hard straight bristle material not otherwise readily adapted to employment in tufted brushes in accordance with prior art procedures. Steel wire having a Knoop hardness of 600 and even of 700 or 800 may thus be employed inasmuch as such bristles are not required to be deformed in the manufacture of the novel tufts of this invention and long fracture thereof in use is inhibited by the elastomeric material in which the basal portions of the bristles are seated and also by the fact that the bristles mutually support one another to a considerable degree as a result of their skewed positions. The tuft .gradually opens out toward the operative end of the tuft with the bristles being relatively closely compacted in the slightly necked region A-A and then gradually spreading outwardly from such region. In consequence, when a bristle is flexed through engagement with the work in use, such bristle will be supported to a gradually increasing extent inwardly toward the base thereof with resultant gradual increasing support thereof by the adjacent bristles in a manner to prevent any localized concentration of stress therein. If desired, the tuft may be further supported by an outer bridle of the type disclosed and claimed in the co-pending application of Vernon K. Charvat, Serial No. "00,496, filed December 3, 1957, now Patent No. 2,989,767.

The brush bristle material may be hard steel Wire with or without a thin plastic coating applied and preferably bonded thereto as by means of an epoxy resin adhesive.

The preferred angle of skewing the bristles, relative to the longitudinal axis of the tuft, is usually plus or minus 2 although in some special cases it may be desired to skew the bristles as much as or more. When the brushes of this invention are employed for such operations as cleaning work surfaces, removal of burrs, and finishing tire molds, a surface finish is produced far superior to that achieved with brushing tools presently commercially employed, especially those with crimped fill wire. The tufts may be formed with a center core or pilot such as is sometimes now used in end brushes, and any desired shape of tuft may be produced by selection of an appropriate sleeve or ferrule to grip the base end. Thus, tufts may be formed of generally square, elliptical, or round cross-section as may be desired. When using wire bristles, the base end of the tuft may be set in solder in known manner although elastomeric material is much preferred.

-It -will be seen from the foregoing that a novel form of brush construction has been provided which is relatively simple of manufacture and permits the production of brushes and especially power driven rotary brushes of increased effectiveness coupled with longer useful life.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A bristle tuft for use in the manufacture of brushes comprising a bundle of straight hard metal wire brush bristles in which the bristles are slightly skewed circumferentially of said bundle to provide respective bundle end portions of greater diameter than an intermediate relatively tightly compacted necked portion, one such end portion being bonded together to secure such bristles together as a tuft in such skewed relationship.

2. The bristle tuft of claim 1, wherein said bristles of hard straight wire are thus bonded together by foamed elastomcric material.

3. A brush comprising a support element having a socket therein and a bristle tuft secured in such socket, said bristle tuft comprising a bundle of straight hard metal Wire brush bristles in which the bristles are slightly skewed circumferentially of said bundle to provide respective bundle end portions of greater diameter than an intermediate relatively tightly compacted necked portion, one such end portion being bonded together to secure such bristles together as a tuft in such skewed relationship.

4. A brush in accordance with claim 3, wherein such support element is in the form of a cup shaped holder, the lip of such cup being turned in to provide a constricted opening through which said bristles extend.

5. A brush in accordance with claim 3, wherein a plurality of said sockets are mounted on a central rotatable hub with said bristle tufts extending generally radially outwardly of the axis of rotation of said hub.

References Cited in the file of this patent UNITED STATES PATENTS 934,058 Farrar Sept. 14, 1909 1,372,108 Timmis Mar. 22, 1921 1,867,487 Barnett et al July 12, 1932 1,883,425 Vroom Oct. 18, 1932 2,756,452 Nielsen July 31, 1956 2,950,495 Stingley Aug. 30, 1960 2,989,767 Char-vat June 27, 1961 FOREIGN PATENTS 549,722 Germany May 2, 1932 -100,184 Australia Jan. 26, 1937 726,940 Great Britain Mar. 23, 1 955 

1. A BRISTLE TUFT FOR USE IN THE MANUFACTURE OF BRUSHES COMPRISING A BUNDLE OF STRAIGHT HARD METAL WIRE BRUSH BRISTLES IN WHICH THE BRISTLES ARE SLIGHTLY SKEWED CIRCUMFERENTIALLY OF SAID BUNDLE TO PROVIDE RESPECTIVE BUNDLE END PORTIONS OF GREATER DIAMETER THAN AN INTERMEDIATE RELATIVELY TIGHTLY COMPACTED NECKED PORTION, ONE SUCH END 